Numerous situations exist in which a body cavity needs to be catheterized to achieve a desired medical goal. One relatively common situation is to provide nutritional solutions or medicines directly into the stomach or intestines. A stoma is formed in the stomach or intestinal wall and a catheter is placed through the stoma. This surgical opening and/or the procedure to create the opening is common referred to as “gastrostomy”. Feeding solutions can be injected through the catheter to provide nutrients directly to the stomach or intestines (known as enteral feeding). A variety of enteral feeding devices have been developed over the years, including some having a “low profile” exterior portion which sits on a patient's skin, as well as those having the more traditional or non-low profile configurations. These enteral feeding devices are also known as “percutaneous transconduit catheters”, “percutaneous transconduit tubes”, “gastrostomy catheters”, “percutaneous gastrostomy catheters”, “PEG catheters” or “enteral feeding catheters”. U.S. Pat. No. 6,019,746 for a “Low Profile Balloon Feeding Device” issued to Picha et al. on Feb. 1, 2000, provides an example of one device.
An enteral feeding device serves as the pathway through the stoma for transconduit of feeding solution into the stomach or intestine. During feeding, the enteral feeding device is often linked to the feeding solution via a tube with a connector. When combined the tube and connector form an extension set. Because a pressurizing source, e.g. a pump that drives the feeding solution through the tube and into and through the enteral feeding device, and because feeding may take several hours, e.g. overnight while a patient is sleeping, maintaining a robust and leak proof connection between the tube and the enteral feeding device is an important feature of the connector. It is also very desirable that the connection withstand twisting, torquing and pulling forces generated by movement of a patient.
However, a problem of low profile and non-low profile enteral feeding devices is the difficulty in connecting and disconnecting the extension sets to and from the enteral feeding device base or head. Many prior art enteral feeding devices have a low profile base and an indwelling catheter which extends from the base. A distal end of the catheter of such a device/assembly often includes a balloon which may be expanded to hold the catheter in a position in a body lumen, such as a stomach lumen.
An enteral feeding device often uses a plug to occlude the feeding passage opening in the base. This plug is attached to the device by a tether. Prior to connecting an extension set to such a conventional enteral feeding device, the step of removing the plug from the base to allow access to the feeding passage opening is required.
Other conventional enteral feeding devices are designed with a base or “head” having a locking cover member in the feeding passage opening to an indwelling catheter. The locking cover member is configured to receive a mating or interlocking connector. Generally speaking, these locking cover members have a keyway, a groove, and a stop member and they incorporate a slot to provide a design that is similar to the female portion of a bayonet fitting. A suitable connector that fits into the locking cover member has a dispensing projection and a key portion attached to that projection. Such a connector is pushed into the locking cover member and twisted in place until it interlocks. Exemplary illustrations of these conventional features may be found in the above referenced U.S. Pat. No. 6,019,746.
Connecting, changing and/or disconnecting a tube having an interlocking connector to/from a locking cover member like that of U.S. Pat. No. 6,019,746 can be a surprisingly difficult. When visibility of the base of the enteral feeding device is limited, e.g. if the patient is overweight, if it is dark, aligning and maneuvering the interlocking connector in or out of the base must rely on touch only. If the patient has impaired motor skills, fitting an interlocking connector in the locking cover member presents challenges of positioning, pushing and twisting. Yet, without being sure that this type of connector is correctly connected to the device, there is a risk of leaking gastric contents and or feeding solution onto a patient's skin surface, clothing, and the like. Further, when this type of connector sits tightly within the base, it may be difficult to remove, thereby requiring extensive pulling, movement of the connected extensions set and base and even unwanted displacement of the base, all of which can cause leakage or irritate a sensitive stoma site.
Some conventional interlocking connectors are configured to allow partial rotation within the base after the connector has been fitted in place. That is, after the inserted interlocking connector in the locking cover member is twisted so the key portion travels past a “detent”, the interlocking connector can rotate between a position where the key portion contacts a stop and a position where the key portion contacts a detent. Unfortunately, the limited range of motion allows the interlocking connector to transmit torquing force to the enteral feeding catheter. This transfer of force may cause the catheter to twist or pull which can cause leakage or irritate a sensitive stoma site. If sufficient force is inadvertently encountered, the key portion of the interlocking connector may be forced past the detent as it would be when a patient or care give is disconnecting the locking connector. After the key portion is forced past the detent, it can readily align with the slot/keyway thereby allowing the extension set to inadvertently become completely disconnected.
These conventional connectors have evident drawbacks that remain unresolved.
The popularity of enteral feeding devices having low profile heads or bases has also resulted in a conversion kit that provides a low-profile base or head component that is clamped onto a percutaneously inserted catheter (i.e., catheter tubing) that is inserted through the abdominal wall to a patient's stomach. Such a low-profile conversion kit is described in U.S. Pat. No. 5,549,657. According to that patent, base or head component has an anti-reflux valve assembly and a two-part clamp. After the base or head component is clamped on the end of a catheter, it functions as the base or head for the catheter. The anti-reflux valve assembly includes a circular seat. A recess located beneath the seat is configured to receive opposed lips of a snap-fit connector that snaps onto the circular seat. An example of such a low-profile conversion kit is commercially available as the Gaurderer Genie™ PEG System Kit available from Bard Nordic (Helsingborg, Sweden), a subsidiary of C.R. Bard Inc.
When a patient is ready to be fed using such a snap-fit connector, the connector is snap fitted onto the anti-reflux valve assembly by pressing the connector against the anti-reflux valve assembly to urge the lips of the connector over the circular seat and into the recess located beneath the circular seat. When feeding is complete, the snap-fit connector is removed by prying or pulling on a set of opposed, reinforced ears. Attachment and detachment of the snap-fit connector is facilitated by a set of opposed slots that enhances axial and radial distortion and flexure of only the central portion of the snap-fit connector when a force is applied to one or both of the opposed ears.
Connecting, changing and/or disconnecting a snap-fit connector to/from such a low-profile enteral feeding head or base may also be a surprisingly difficult exercise at least for the same reasons as conventional interlocking connector. Moreover, the application of force to press the snap-fit connector onto the head and also to pry it off the head transfers forces directly to the enteral feeding device which may create discomfort and cause irritation to the sensitive stoma site. The low-profile of the head and its relatively small size (e.g., typically between about 13 mm and 25 mm in diameter) also creates difficulty in that opposed ears of the snap-fit connector can extend over the ends of the head and lie adjacent or even against the skin of the patient to make it difficult to grasp or pinch the ears between the fingers.
Accordingly, there is a need for a connector for coupling a medical fluid supply tube to the head of a catheter device having a circular hub. For example, there is a need for an enteral feeding extension set connector which permits a user or health care provider to easily connect and disconnect an extension set to the base of an enteral feeding device. Such a system would permit a user or health care provider to easily and reliably disconnect the previous, used, connector and connect a new connector, desirably without needing to see the base of the device.